Self-correcting abacus



FIG. 1 is a top plan view of a self-correcting abacus, showing my new design, with the vertical rods removed for ease of disclosure;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a back elevation view thereof;

FIG. 4 is a right side elevation view thereof, the left side being a mirror image thereof;

FIG. 5 is a top plan view thereof, shown with the vertical rods attached and with the drawer in an open position and the drawer compartment lids fully retracted;

FIG. 6 is a front elevation view thereof;

FIG. 7 is a rear elevation view thereof;

FIG. 8 is a right side elevation view thereof with the drawer shown extended;

FIG. 9 is a perspective view thereof, with the drawer compartment lids partially retracted; and,

FIG. 10 is a cross-section view thereof, taken along line 10—10 of FIG. 5, showing the slots which the compartment lids fit into when fully closed.

The broken lines depict environmental subject matter only and form no part of the claimed design. 

The ornamental design for a self-correcting abacus, as shown and described. 